The bus was traveling from the coastal resort town of Marmaris to the southeastern province of Mardin.
The incident occurred around 1:15 am at the exit of the Sarıyar Tunnel in the Yenikaş neighborhood on the D-400 highway.
The bus collided with a barrier before overturning, leaving passengers trapped inside.
Emergency response teams including health staff, gendarmerie, AFAD, and firefighters rushed to the scene to assist the injured and secure the area.
All of the injured were swiftly transported to nearby hospitals for medical attention.
Mersin Governor Ali Hamza Pehlivan confirmed the accident in a written statement, explaining that it occurred approximately 170 kilometers from the city center on the Mersin-Antalya highway.
He further revealed that the bus was carrying 40 passengers and 3 crew members at the time of the crash.
The cause of the accident is currently under investigation. Authorities are analyzing the wreckage and interviewing witnesses to determine what led to the tragedy. (ILKHA)